src/basic/strxcpyx.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 /*
   4  * Concatenates/copies strings. In any case, terminates in all cases
   5  * with '\0' and moves the @dest pointer forward to the added '\0'.
   6  * Returns the remaining size, and 0 if the string was truncated.
   7  *
   8  * Due to the intended usage, these helpers silently noop invocations
   9  * having zero size.  This is technically an exception to the above
  10  * statement "terminates in all cases".  It's unexpected for such calls to
  11  * occur outside of a loop where this is the preferred behavior.
  12  */
  13
  14 #include <stdarg.h>
  15 #include <stdio.h>
  16 #include <string.h>
  17
  18 #include "strxcpyx.h"
  19
  20 size_t strpcpy(char **dest, size_t size, const char *src) {
  21         size_t len;
  22
  23         assert(dest);
  24         assert(src);
  25
  26         if (size == 0)
  27                 return 0;
  28
  29         len = strlen(src);
  30         if (len >= size) {
  31                 if (size > 1)
  32                         *dest = mempcpy(*dest, src, size-1);
  33                 size = 0;
  34         } else if (len > 0) {
  35                 *dest = mempcpy(*dest, src, len);
  36                 size -= len;
  37         }
  38
  39         *dest[0] = '\0';
  40         return size;
  41 }
  42
  43 size_t strpcpyf(char **dest, size_t size, const char *src, ...) {
  44         va_list va;
  45         int i;
  46
  47         assert(dest);
  48         assert(src);
  49
  50         if (size == 0)
  51                 return 0;
  52
  53         va_start(va, src);
  54         i = vsnprintf(*dest, size, src, va);
  55         if (i < (int)size) {
  56                 *dest += i;
  57                 size -= i;
  58         } else
  59                 size = 0;
  60         va_end(va);
  61         return size;
  62 }
  63
  64 size_t strpcpyl(char **dest, size_t size, const char *src, ...) {
  65         va_list va;
  66
  67         assert(dest);
  68         assert(src);
  69
  70         va_start(va, src);
  71         do {
  72                 size = strpcpy(dest, size, src);
  73                 src = va_arg(va, char *);
  74         } while (src);
  75         va_end(va);
  76         return size;
  77 }
  78
  79 size_t strscpy(char *dest, size_t size, const char *src) {
  80         char *s;
  81
  82         assert(dest);
  83         assert(src);
  84
  85         s = dest;
  86         return strpcpy(&s, size, src);
  87 }
  88
  89 size_t strscpyl(char *dest, size_t size, const char *src, ...) {
  90         va_list va;
  91         char *s;
  92
  93         assert(dest);
  94         assert(src);
  95
  96         va_start(va, src);
  97         s = dest;
  98         do {
  99                 size = strpcpy(&s, size, src);
 100                 src = va_arg(va, char *);
 101         } while (src);
 102         va_end(va);
 103
 104         return size;
 105 }